Question 555 of 1,663
DBS-C01 Workload-Specific Database Design Practice Question
A company uses Amazon RDS for PostgreSQL to store sensor data. Each sensor sends a row every second. The table has grown to 500 GB and queries filtering on a timestamp column are slow even with an index. The team wants to improve query performance while keeping the data online. Which approach should they take?
⚠ Common exam trap
Watch out — candidates often assume adding indexes or using read replicas will solve performance issues for large time-series tables, but they fail to recognize that partitioning directly reduces the data scanned per query, which is the root cause of slow filtering on timestamp columns.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Partition the table by time using PostgreSQL table partitioning
PostgreSQL table partitioning by time (e.g., by day or month) allows the query planner to prune partitions that do not match the timestamp filter, drastically reducing the amount of data scanned. This is the most effective approach for time-series data because it maintains online access and improves query performance without requiring a migration or additional replicas.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Partition the table by time using PostgreSQL table partitioning
Why this is correct
Partitioning by time allows partition pruning, significantly improving query performance on timestamp filters.
- ✗
Migrate to Amazon Aurora PostgreSQL and enable parallel query
Why it's wrong here
Parallel query can speed up some queries but partitioning is a more fundamental optimization for time-series data.
- ✗
Add more indexes on the timestamp column
Why it's wrong here
Additional indexes on the same column are redundant and may degrade write performance.
- ✗
Create a read replica and direct queries to the replica
Why it's wrong here
Read replicas distribute read load but do not improve performance of individual queries against large tables.
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Last reviewed: Jul 4, 2026
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.
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